Wheel spacers for positioning or spacing reinforcing rods which reinforce cementitious structures relative an object, such as a mold or wall containing the structure, during the manufacture of the structure are well known in the art. Such wheel spacers typically are circular in form on an outer wall thereof and have an inner saddle formed by an inner wall thereof in which the rod is held. The rod, seated in the saddle, is spaced from the object by abutment of the outer wall against the object.
For example, U.S. Pat. No. 3,694,989 teaches a wheel spacer having a saddle for the rod essentially at the center thereof, relative the outer wall which abuts the object for spacing the rod therefrom. The rod is held in place in the saddle by a locking member which is slid into a groove, via a gap in the outer wall, leading into the saddle. Unfortunately, if equal and uniform spacing of each rod relative the object is desired, due to the gap in the outer wheel, each wheel spacer of this type must be positioned carefully with regard to every other wheel spacer of this type to ensure that either the gap abuts the object or the solid circular part of the spacer abuts the object. Otherwise, different rods in the structure may not be equally spaced relative the object.
U.S. Pat. No. 5,542,785 discloses a wheel spacer which partially circumvents the aforementioned difficulty. The spacer consists of two largely symmetrical and semicircular sections which each have a respective saddle extending on an inner wall thereof towards the respective outer wall thereof. Thus, the rod may be placed or aligned with one of the saddles of one section and then sections connected together in abutment with one another, notably the outer walls thereof. Thus, the rod is held in the saddles and there is no substantially gap in between the outer walls. Unfortunately, the attachment members by which the two sections are attached, essentially arms having single protrusions or clips on the ends thereof, allow for little adjustment of the space provided by the saddle, and thus the size of the rod held thereby. Further removal of the rod, which may be occasionally desired prior to manufacture of the rod, may be rendered difficult as the attachment members may make separating of the attachment members difficult. Further, and inconveniently, the rod must be precisely positioned in one of the saddles prior to attachment of the sections together as there is no means provided for retaining and guiding the rod into the saddles as the sections are being connected.
U.S. Pat. No. 5,347,787 discloses a single piece wheel spacer having two sections joined by a hinged portion on the outer wall, and which obviates some of the aforementioned difficulties by providing retaining arms which guide the rod towards the saddles. However, as the two sections of the wheel spacer are permanently attached to one another at the hinged portion, the wheel spacer may, in some circumstances where space is limited, be difficult to place around the rod. Further, removal of the spacer from the rod in the event that repositioning of the spacer is desired, for example before apply cementitious material for manufacture of the cementitious structure may be encumbered due the connection of the sections at the hinged portion. In addition, during seating of the rod in the saddles, there is always a risk that the rod will fall between the saddles and the hinged portion which may break the hinged portion or require lifting of the rod back into alignment with the saddles.
Accordingly, there is a need for an improved wheel spacer for spacing a reinforcing rod during manufacturing of a cementitious structure.